Prostate cancer is the one of the most common cancers diagnosed in the United States. A prostate cancer diagnosis can vary from a low- or intermediate-risk to a high-risk diagnosis, which means that the patient has a low-, intermediate-, or high-risk of pathological and biochemical outcomes after treatment (e.g., by radical prostatectomy); metastasis; prostate cancer-specific mortality; and all-cause mortality. A diagnosis of a particular risk category can determine the course of treatment, which can, for example, range from monitoring, in the case of low-risk cancers, to radiation or surgical procedures for higher risk cancers.
Common methods of screening for prostate cancer include a digital rectal exam (DRE) and serum prostate-specific antigen (sPSA) screening, which can be administered alone or in combination. The use of DRE is not favored by patients, and sPSA testing is controversial. One prostate cancer urine test measures the cancer-specific non-coding transcript PCA3 from released prostate cancer cells, but only has a sensitivity of 65% and a specificity of 66%.
Thus, while screening men for prostate cancer decreases mortality from the disease, a need remains for a more accurate and non-invasive means of screening for prostate cancer. There is also a need for an accurate, non-invasive means of distinguishing prostate cancer in different risk categories with the concern of overtreatment. For example, low-risk prostate cancer patients can remain healthy for a long time without undergoing invasive and painful surgery with potentially harmful side effects, and, thus, are considered ideal candidates for observation-based therapies, such as watchful waiting and active surveillance.